/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.tomcat.util.scan;

import java.io.IOException;
import java.io.InputStream;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.jar.JarEntry;

/**
 * Implementation of {@link Jar} that is optimised for non-file based JAR URLs
 * (e.g. JNDI based URLs of the form jar:jndi:...).
 */
public class UrlJar implements Jar {

	private NonClosingJarInputStream jarInputStream = null;
	private URL url = null;
	private JarEntry entry = null;

	public UrlJar(URL url) throws IOException {
		this.url = url;
		this.jarInputStream = createJarInputStream();
	}

	@Override
	public boolean entryExists(String name) throws IOException {
		JarEntry entry = jarInputStream.getNextJarEntry();
		while (entry != null) {
			if (name.equals(entry.getName())) {
				break;
			}
			entry = jarInputStream.getNextJarEntry();
		}

		return entry != null;
	}

	@Override
	public InputStream getInputStream(String name) throws IOException {
		JarEntry entry = jarInputStream.getNextJarEntry();
		while (entry != null) {
			if (name.equals(entry.getName())) {
				break;
			}
			entry = jarInputStream.getNextJarEntry();
		}

		if (entry == null) {
			return null;
		} else {
			return jarInputStream;
		}
	}

	@Override
	public void close() {
		if (jarInputStream != null) {
			try {
				jarInputStream.reallyClose();
			} catch (IOException ioe) {
				// Ignore
			}
		}
	}

	private NonClosingJarInputStream createJarInputStream() throws IOException {
		JarURLConnection jarConn = (JarURLConnection) url.openConnection();
		URL resourceURL = jarConn.getJarFileURL();
		URLConnection resourceConn = resourceURL.openConnection();
		resourceConn.setUseCaches(false);
		return new NonClosingJarInputStream(resourceConn.getInputStream());
	}

	@Override
	public void nextEntry() {
		try {
			entry = jarInputStream.getNextJarEntry();
		} catch (IOException ioe) {
			entry = null;
		}
	}

	@Override
	public String getEntryName() {
		if (entry == null) {
			return null;
		} else {
			return entry.getName();
		}
	}

	@Override
	public InputStream getEntryInputStream() throws IOException {
		return jarInputStream;
	}

	@Override
	public void reset() throws IOException {
		close();
		jarInputStream = createJarInputStream();
	}
}
